1982 Evinrude 50HP RPM problems

[Kurse]

Hello everyone,

I'm brand new to the forum and am looking for some help with a particular problem. And just maybe I can provide insight into other problems down the line!

I have an 1982 Evinrude 50 HP motor that starts well bu after running for a few minutes the RPM starts to increase on it's own and then it will spit back. RPM then falls to normal and it will continue doing this and sometimes the RPM will go even higher, almost 1/2 throttle.

It is running with garden hose + muffs.

So far I've done a few things:
- taken off the carbs and blown it out with air
- sealed the gaskets between the carbs & block
- put in new plugs

After running the motor again I removed the plugs and found the top plugs burning darker than the bottom. I grounded the plugs and turned the engine over to check spark and found them to be both strong.

Hopefully someone has some sight out there!

Thanks
Kyle

 

[jonesg]

Re: 1982 Evinrude 50HP RPM problems

Sounds like a lean sneeze.
Could be carbs , air leak or timing is over advanced, could also be head gasket leaking. I'd check carbs and timing first.
Do the carb plates close fully at idle?
Has it been link/sync'd ?
Do you have a timing light, they're cheap.
And the shop manual?
www.outboardbooks.com
Tools and manual cost less than putting it in the shop for almost anything.